In order to increase the speed of integrated circuit devices it is desired to manufacture the devices in as small a size as possible. By manufacturing the semiconductor devices with ever smaller sized features, the thickness of the barrier metal thin film for interconnect metallization within the device is also forced to be reduced.
However, the properties of the barrier metal thin film, such as its anti-diffusion capability, low resistivity, high density, step coverage, and other such properties, are required to remain the same or even improve. Conventional metal organic chemical vapor deposition (MOCVD), however, does not allow for the manufacture of films having a smaller thickness while having the same, or improved, film properties as thicker films.
Plasma densification performed on conventional chemical vapor deposition (CVD) barrier metal films may extend the capabilities of conventional CVD technology. However, due to the anisotropic nature of the plasma treatment, the film properties of the barrier metal film deposited on a side wall of a trench or a via are different from the film properties of the film deposited on the horizontal surfaces of the deposition surface. The blocking diffusion capability of the film is therefore reduced on the side wall of the trench or the via.
Additionally, conventional CVD barrier films contain carbon and other impurities that affect the density and resistivity of as-deposited barrier metal thin films. Accordingly, current technology is limited with regard to the thickness to which barrier metal films can be reduced and with regard to the properties of barrier metal films.